Electronic components with terminals and spring contact elements extending from areas which are remote from the terminals

ABSTRACT

Spring contact elements are fabricated at areas on an electronic component remote from terminals to which they are electrically connected. For example, the spring contact elements may be mounted to remote regions such as distal ends of extended tails (conductive lines) which extend from a terminal of an electronic component to positions which are remote from the terminals. In this manner, a plurality of substantially identical spring contact elements can be mounted to the component so that their free (distal) ends are disposed in a pattern and at positions which are spatially-translated from the pattern of the terminals on the component. The spring contact elements include, but are not limited to, composite interconnection elements and plated-up structures. The electronic component includes, but is not limited to, a semiconductor device, a memory chip, a portion of a semiconductor wafer, a space transformer, a probe card, a chip carrier, and a socket.

CROSS-REFERENCE TO RELATED APPLICATIONS:

This patent application is a continuation-in-part of commonly-owned,copending U.S. Provisional Patent Application Ser. No. 60/051,366 filedJun. 30, 1997, which is also a continuation-in-part of commonly-owned,U.S. patent application Ser. No. 08/852,152 filed May 6, 1997 (status:pending) and its counterpart PCT Patent Application No. US97/08634 filedMay 15, 1997 (status: pending)

TECHNICAL FIELD OF THE INVENTION

The present invention relates to resilient (spring) contact(interconnection) elements (structures) suitable for effectingconnections between electronic components and, more particularly, tomicrominiature spring contact elements.

BACKGROUND OF THE INVENTION

Commonly-owned U.S. patent application Ser. No. 08/152,812 filed Nov.16, 1993 (now U.S. Pat. No. 5,476,211, issued Dec. 19, 1995), and itscounterpart commonly-owned copending "divisional" U.S. patentapplications Ser. Nos. 08/457,479 filed Jun. 1, 1995 (status: pending)and 08/570,230 filed Dec. 11, 1995 (status: pending), disclose methodsfor making resilient interconnection elements (spring contact elements)for microelectronics applications involving mounting an end of aflexible elongate core element (e.g., wire "stem" or "skeleton") to aterminal on an electronic component, coating the flexible core elementand adjacent surface of the terminal with a "shell" of one or morematerials having a predetermined combination of thickness, yieldstrength and elastic modulus to ensure predetermined force-to-deflectioncharacteristics of the resulting spring contacts. Exemplary materialsfor the core element include gold. Exemplary materials for the coatinginclude nickel and its alloys. The resulting spring contact element issuitably used to effect pressure, or demountable, connections betweentwo or more electronic components, including semiconductor devices.

Commonly-owned, copending U.S. patent application Ser. No. 08/340,144filed Nov. 15, 1994 (status: pending) and its corresponding PCT PatentApplication No. PCT/US94/13373 filed Nov. 16, 1994 (published asWO95/14314 May 26, 1995, pending), both by KHANDROS and MATHIEU,disclose a number of applications for the aforementioned spring contactelements, and also discloses techniques for fabricating contact pads(contact tip structures) at the ends of the spring contact elements.

Commonly-owned, copending U.S. patent application Ser. No. 08/452,255filed May 26, 1995 (status: pending) and its corresponding PCT PatentApplication No. PCT/US95/14909 filed Nov. 13, 1995 (published asWO96/17278 Jun 6, 1996, pending) disclose additional techniques andmetallurgies for fabricating spring contact elements as compositeinterconnection structures and for fabricating and mounting contact tipstructures to the free ends (tips) of the composite interconnectionelements.

Commonly-owned, copending U.S. patent application Ser. No. 08/819,464filed Mar 17, 1997 (status: pending) and its counterpart PCT PatentApplication No. US97/08606 filed May 15, 1997 (status: pending) disclosea technique whereby a plurality of elongate tip structures havingdifferent lengths than one another can be arranged so that their outerends are disposed at a greater pitch than their inner ends. Their inner,"contact" ends may be collinear with one another, for effectingconnections to electronic components having terminals disposed along aline, such as a centerline of the component. Additional contact tipstructure methods and apparatus are disclosed in these patentcommonly-owned applications.

The present invention addresses and is particularly well-suited tomaking interconnections to modern microelectronic devices (components)having their terminals (bond pads) disposed at a fine-pitch. As usedherein, the term "fine-pitch" refers to microelectronic devices thathave their terminals disposed at a spacing of less than 5 mils, such as2.5 mils or 65 μm. As will be evident from the description that follows,this is preferably achieved by taking advantage of the close tolerancesthat readily can be realized by using lithographic rather thanmechanical techniques to fabricate the contact elements.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved techniquefor fabricating spring contact elements.

Another object of the invention is to provide a technique forfabricating spring contact elements using processes that are inherentlywell-suited to the fine-pitch close-tolerance world of microelectronics.

Another object of the invention is to provide a technique forfabricating microminiature spring contact elements directly on activeelectronic components, such as semiconductor devices, without damagingthe semiconductor devices. This includes fabricating microminiaturespring contact elements on semiconductor devices resident on asemiconductor wafer, prior to their being singulated therefrom.

Another object of the invention is to provide a technique forfabricating spring contact elements that are suitable for socketing(releasably connecting to) electronic components such as semiconductordevices, such as for performing burn-in on said devices.

Another object of the invention is to provide a technique forfabricating spring contact elements which provide space translation ofthe terminals of an electronic component to which they are mounted. Asused herein, the term "space translation" means that the tips (distalends) of the spring contact elements are disposed at different spacing(pitch) and/or orientation than the terminals of the electroniccomponent to which they are connected.

According to the invention, a spring contact element is fabricated on anelectronic component such as an active semiconductor device, a memorychip, a portion of a semiconductor wafer, a space transformer, a probecard, a chip carrier, or a socket, at a position on the electroniccomponent which is remote (spatially translated) from a terminal towhich it is electrically connected. The electrical connection betweenthe spring contact element and the terminal is suitably a conductiveline originating at the terminal. The spring contact element isfree-standing, having a base end which is mounted to the electroniccomponent, such as at a position on the conductive line which is remotefrom the terminal, a contact (tip) end, and a resilient main bodyportion between the base end and the tip end.

The spring contact elements are any resilient, freestanding contactstructures. An example of a resilient, freestanding contact structure isdisclosed in commonly-owned U.S. Pat. No. 5,476,211 issued Dec. 19,1995, which is incorporated by reference herein. Another example of aresilient, freestanding contact structure is disclosed incommonly-owned, copending U.S. patent application Ser. No. 08/802,054filed Feb. 18, 1997 (status: pending) and its counterpart PCT PatentApplication No. US97/08271 filed May 15, 1997 (status: pending), as wellas in the aforementioned US97/08634.

According to an aspect of the invention, a plurality spring contactelements are mounted to an electronic component and electricallyconnected to a corresponding plurality of terminals on the electroniccomponent in a manner to effect "space translation"--in other words, sothat the layout and/or pitch of the component terminals is differentthan the layout and/or pitch of the tips of the spring contact elements.For example, the terminals of the electronic component are disposed at afirst pitch in a peripheral pattern and the tips of the spring contactelements are disposed in an area array at a second pitch, or vice-versa.

The aforementioned U.S. patent application Ser. No. 08/340,144 and PCTPatent Application No. US94/13373 disclose a one type ofpitch-translation which is effected by shaping selected ones of thefree-standing resilient contact structures differently than other one ofthe free-standing resilient contact structures. See FIGS. 23 and 24therein. Such a technique has the drawback that different "style" springcontact elements need to be designed, manufactured and mounted to asingle electronic component. This can cause problems in processing,particularly if certain steps in the manufacturing process have narrowprocess windows.

According to an aspect of the invention, a plurality of spring contactelements are manufactured so that they are substantially similar (suchas identical) to one another, and space-translation is effected bytailoring a relatively process-insensitive part of the overall springcontact elements. To wit, at least some of, including all of, the springcontact elements on a given electronic component are provided withelongate "tails", which may be conductive lines extending from the baseend of the spring contact element to the terminal of the electroniccomponent to which it is electrically connected.

In an embodiment of the invention, the tails are elongate conductivelines formed using conventional semiconductor processing techniquesextending along the surface of the component. A one (proximal) end ofthe conductive line overlies a terminal (e.g., bond pad) of theelectronic component and is joined thereto. The base end of a springcontact element is joined to an other position on the conductive line,such as at the remote (distal) end of the conductive line. Thisembodiment is suited to fabricating spring contact elements which arecomposite interconnection elements directly upon the conductive linewhich effects space translation. This embodiment is also suited tojoining pre-fabricated spring contact elements to the remote positionson the conductive lines.

In another embodiment of the invention, the tails are elongateconductive lines formed using conventional semiconductor processingtechniques extending along the surface of the component. A one(proximal) end of the conductive line overlies a terminal (e.g., bondpad) of the electronic component. The base end of a spring contactelement is integrally formed with an other remote (distal) end of theconductive line. This embodiment is well suited to manufacturing springcontact elements which are plated-up structures and the elongateconductive line tails extending to terminals of the electronic componentin one fell swoop.

According to an aspect of the invention, the tails of the spring contactelements can extend in a straight line (linearly) along the surface ofthe electronic component to the base end of the spring contact elementto effect "simple" space-translation such as fan-out (or fan-in). Or,the tails of the spring contact elements can "wander" (or meander) alongthe surface of the electronic component including, if necessary crossingover one another to effect more complex space-translation schemes.

A benefit of the present invention is that the contact layout of anexisting electronic component can be modified, after the electroniccomponent has already been completely manufactured. For example, acompleted (finished) semiconductor device has a number of bond padterminals accessible on a surface thereof through openings in apassivation layer. If a plurality of identical spring contact elementswere mounted to or fabricated upon those terminals, the tips of thespring contact elements would mirror the layout of the bond pads. Thepresent invention essentially "relocates" the terminals (at least aportion thereof) so that the tips of the spring contact elements canhave a completely different layout than the bond pads of thesemiconductor device. The tails or conductive lines of the presentinvention have a proximal end which is directly atop an existingterminal of an existing electronic component and a remote region (suchas a distal end) which, in essence, serves as a "relocated terminal" forthe electronic component.

The spring contact elements of this invention are suitable for makingeither temporary or permanent electrical connections to terminals ofanother electronic component such as a printed circuit board (PCB)interconnection substrate.

For making temporary connections, the component upon which the springcontact elements are fabricated is brought together with anotherelectronic component so that the tip ends of the spring contact elementsare in pressure contact with terminals of the other electroniccomponent. The spring contact elements react resiliently to maintaincontact pressure and electrical connections between the two components.

For making permanent connections, the component upon which the springcontact elements are fabricated is brought together with anotherelectronic component, and the tip ends of the spring contact elementsare joined, such as by soldering or brazing or with a conductiveadhesive, to terminals of the other electronic component. The springcontact elements are compliant, and accommodate differential thermalexpansion between the two electronic components.

The spring contact element is suitably formed of at least one layer of ametallic material selected for its ability to cause the resultingcontact structure to function, in use, as a spring (i.e., exhibitelastic deformation) when force is applied to its contact (free) end.

The spring contact elements of the present invention can be fabricateddirectly on the surface of a semiconductor device, or on the surfaces ofa plurality of semiconductor devices resident on a semiconductor wafer.In this manner, a plurality of semiconductor devices resident on asemiconductor wafer can be "readied" for burn-in and/or test prior tobeing singulated from the semiconductor wafer.

Other objects, features and advantages of the invention will becomeapparent in light of the following description thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will be made in detail to preferred embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. The drawings are intended to be illustrative, not limiting.Although the invention will be described in the context of thesepreferred embodiments, it should be understood that it is not intendedto limit the spirit and scope of the invention to these particularembodiments. Certain elements in selected ones of the drawings areillustrated not-to-scale, for illustrative clarity. Often, similarelements throughout the drawings are referred to by similar referencesnumerals. For example, the element 199 may be similar in many respectsto the element 299 in another figure. Also, often, similar elements arereferred to with similar numbers in a single drawing. For example, aplurality of elements 199 may be referred to as 199a, 199b, 199c, etc.

FIG. 1A is a side cross-sectional view of a technique for making aspring contact element which is a composite interconnection element,according to the invention.

FIG. 1B is a side cross-sectional view of a further step in thetechnique for making the spring contact element of FIG. 1A, according tothe invention.

FIG. 1C is a side cross-sectional view of a further step in thetechnique for making the spring contact element of FIG. 1B, according tothe invention.

FIG. 2A is a side cross-sectional view of a technique for making aspring contact element which is a plated-up structure, according to theinvention.

FIG. 2B is a side cross-sectional view of a further step in thetechnique for making the spring contact element of FIG. 2A, according tothe invention.

FIG. 2C is a perspective view of a further step in the technique formaking the spring contact element of FIG. 2B, according to theinvention.

FIG. 3 is a perspective view of an electronic component having aplurality of spring contact elements mounted to terminals thereof.

FIG. 4 is a perspective view of a technique for forming conductive lineson an existing electronic component.

FIG. 5A is a perspective view of a technique for effectingspace-translation with spring contact elements which are compositeinterconnection elements, according to the invention.

FIG. 5B is a perspective view of a technique for effectingspace-translation with spring contact elements which are plated-upstructures, according to the invention.

FIG. 6A is a schematic (stylized) plan view illustration of anapplication (use) for the spring contact elements having extended tails,according to the invention.

FIG. 6B is a cross-sectional view, taken on a line 6B--6B through FIG.6A, according to the invention.

FIG. 7A is a schematic (stylized) plan view illustration of anotherapplication (use) for the spring contact elements having extended tails,according to the invention.

FIG. 7B is a cross-sectional view, taken on a line 7B--7B through FIG.7A, according to the invention.

FIG. 8A is a perspective view of two spring contact elements which are"composite interconnection elements" mounted to distal regions of aconductive line emanating from a terminal of an electronic component,according to the invention.

FIG. 8B is a perspective view of two spring contact elements which are"plated-up structures" mounted to distal regions of a conductive lineemanating from a terminal of an electronic component, according to theinvention.

FIG. 9 is a schematic plan view of an existing terminal of an electroniccomponent, a "relocated terminal" and a connection therebetween,according to the invention.

FIG. 9A is a perspective view of a technique for forming a relocatedterminal on an electronic component, and effecting an electricalconnection to an existing terminal of the component, according to theinvention.

FIG. 9B is a cross-sectional view, taken on a line 9B--9B through FIG.9A, according to the invention.

FIG. 10 is a schematic plan view of a first step of mounting orfabricating spring contact elements to relocated terminals on anelectronic component, according to the invention.

FIGS. 10A-10C are side-cross sectional views, taken on a line 10--10through FIG. 10 of an embodiment of a technique for mounting orfabricating spring contact elements to relocated terminals on anelectronic component, according to the invention.

FIGS. 10D-10G are side-cross sectional views, taken on a line 10--10through FIG. 10 of another embodiment of a technique for mounting orfabricating spring contact elements to relocated terminals on anelectronic component, according to the invention.

FIGS. 11A-11C are cross-sectional views of a technique for mountingpreviously manufactured spring contact elements which are compositeinterconnection elements to conductive lines on an electronic component,according to the invention.

FIGS. 12A-12C are cross-sectional views of a technique for mountingpreviously manufactured spring contact elements which are plated-upstructures to conductive lines on an electronic component, according tothe invention.

FIGS. 13A and 13B are cross-sectional views of a technique for mountingpreviously manufactured contact tip structures to spring contactelements which are resident on conductive lines (extended tails),according to the invention.

FIG. 14A is a cross-sectional view of a technique for making multi-levelconductive lines on an electronic component, according to the invention.

FIG. 14B is a perspective view, partially broken away, of a techniquefor making conductive lines which cross over one another on anelectronic component, according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The section headings appearing in the description that follows areincluded as an aid to the reader, and are not to be construed in alimiting manner.

An Exemplary Spring Contact Element

The aforementioned commonly-owned U.S. Pat. No. 5,476,211 and PCT PatentApplication No. US94/13373 disclose techniques for fabricating elongatefree-standing resilient contact structures (spring contact elementswhich are composite interconnection elements) on electronic componentsby bonding and shaping an elongate core element (e.g., a gold wire) on aterminal of the component and overcoating the free-standing core elementand an adjacent area (e.g., the terminal) of the component with ametallic material which dominates the mechanical characteristics of theresulting composite interconnection element and securely anchors theresulting composite interconnection element to the terminal of thecomponent.

The aforementioned PCT Patent Application No. US95/14909 discloses, atFIGS. 1C, 1D and 1E thereof, reproduced herein as FIGS. 1A, 1B and 1C,discloses an exemplary technique for fabricating spring contact elementsof the aforementioned composite interconnection type on electroniccomponents which are semiconductor devices. This technique is alsodisclosed at FIGS. 3A, 3B and 3C of commonly-owned, copending PCT PatentApplication No. US95/14885 filed Nov. 15, 1995 (published May 23, 1996as WO96/15459).

FIGS. 1A, 1B and 1C illustrate an exemplary technique for fabricatingresilient, elongate, free-standing spring contact elements which arecomposite interconnection elements on an electronic component 108 whichis a semiconductor device wherein a free end 102a of a wire 102 is fedthrough a capillary 104 and is bonded to a surface of the semiconductordevice 108. In this technique, a conductive layer 120 is first disposedon the surface of the component 108. This layer 120 may be a top metallayer, which is normally intended for bond-out, as defined by openings122 in a passivation layer 124 (typically nitride). In this manner, abond pad would be defined which would have an area corresponding to thearea of the opening 122 in the passivation layer 124. Normally (i.e.,according to the prior art), a wire would be bonded to the bond pad. Ablanket layer 126 of metallic material (e.g., aluminum) is depositedover the passivation layer 124 in a manner that the conductive layer 126conformally follows the topography of the passivation layer 124,including "dipping" into the opening 122 and electrically contacting thelayer 120. A patterned layer 128 of photoresist is applied over thelayer 126 with openings 132 aligned over the openings 122 in thepassivation layer 124. A feature of this technique is that the opening132 is larger than the opening 122. This results in a larger bond area(defined by the opening 132) than is otherwise (as defined by theopening 122) present on the semiconductor die (108). The free end 102aof the wire 102 is bonded to the top (as viewed) surface of theconductive layer 126, within the opening 132. Next the wire isconfigured to have a spring shape and is severed to create afree-standing "wire stem". Next, the wire stem and adjacent area of thecomponent 108 within the opening 132 is overcoated (e.g., plated) withone or more layers of a metallic material (e.g., nickel), resulting in aspring contact element which is a freestanding elongate compositeinterconnection structure. As shown in FIGS. 1B and 1C, the material 134overcoating the wire stem completely envelops the wire stem and alsocovers the conductive layer 126 within the area defined by the opening132 in the photoresist 128. The photoresist 128 is then removed (such asby chemical etching, or washing), and the substrate is subjected toselective etching (e.g., chemical etching) to remove all of the materialfrom the conductive layer 126 except that portion of the layer 126 whichis covered by the material 134 overcoating the wire stem. This resultsin the structure shown in FIG. 1C, a significant advantage of which isthat the resulting spring contact element 130 is securely anchored (bythe coating material 134) to an area (which was defined by the opening132 in the photoresist) which can easily be made to be larger than whatwould otherwise (e.g., in the prior art) be considered to be the contactarea of a bond pad (i.e., the opening 122 in the passivation layer 124).The spring contact element 130 shown in FIG. 1C is a compositeinterconnection element which is elongate and has a base (proximal) endwhich is mounted to the semiconductor device 108 and free (distal) end(tip) at its opposite end for making a pressure contact with a terminal(not shown) of another electronic component (not shown).

Exemplary materials, processes and dimensions

Exemplary materials for the wire 102 include, but are not limited to:gold, aluminum, copper, and their alloys. These materials are typicallyalloyed with small amounts of other metals to obtain desired physicalproperties, such as with beryllium, cadmium, silicon, magnesium, and thelike. It is also possible to use silver, palladium, platinum; metals oralloys such as metals of the platinum group of elements. Solderconstituted from lead, tin, indium, bismuth, cadmium, antimony and theiralloys can be used.

Exemplary materials for the overcoat 134 include, but are not limitedto: nickel, and its alloys; copper, cobalt, iron, and their alloys; gold(especially hard gold) and silver, both of which exhibit excellentcurrent-carrying capabilities and good contact resistivitycharacteristics; elements of the platinum group; noble metals;semi-noble metals and their alloys, particularly elements of thepalladium group and their alloys; tungsten and molybdenum. In caseswhere a solder-like finish is desired, tin, lead, bismuth, indium andtheir alloys can also be used.

Exemplary processes for overcoating the core element (wire stem) 102include, but are not limited to: various processes involving depositionof materials out of aqueous solutions; electrolytic plating; electrolessplating; chemical vapor deposition (CVD); physical vapor deposition(PVD); processes causing the deposition of materials through induceddisintegration of liquid or solid precursors; and the like, all of thesetechniques for depositing materials being generally well known.

Exemplary dimensions for the wire 102 are, but are not limited to: around cross-section wire having a diameter of approximately 1 mil(0.0010 inches) including, but not limited to a diameter in the range of0.7-2.0 mils, preferably in the range of 0.5-3.0 mils.

It is within the scope of this invention that the wire 102 is in theform of a ribbon, having a non-circular cross-section, of theabove-referenced materials. For example, it may be generally rectangularin cross-section, having a first transverse dimension "d1" greater thana second transverse dimension "d2" in a direction orthogonal to thefirst dimension "d1". The dimension "d1" is preferably at least twice(two times) as large (including three, four, and more) as the dimension"d2". For example:

the dimension "d1" (or width) may be 1-10 mils, for example 5.0 mils;and

the dimension "d2" (or thickness) may be 0.3-1.5 mils, for example 1.0mils.

Exemplary dimensions for the various layers of a multilayer overcoat 134are, but are not limited to 0.03 to 5 mils, preferably from 0.05 mils to3 mils, an overall thickness of the overcoat being on the order of 1-3mils.

Another Exemplary Spring Contact Element

Commonly-owned, copending U.S. patent application Ser. No. 08/784,862filed Jan. 15, 1997 (status: pending) and its counterpart PCT PatentApplication No. US97/08604 filed May 15, 1997 (status: pending)disclose, for example at FIGS. 6A-6C thereof, a technique forfabricating free-standing resilient (spring) contact elements on anelectronic component. Generally, a number of insulating layers havingopenings formed therein are aligned and "seeded" with a layer ofconductive material. A mass of conductive material can then be formed(or deposited) in the seeded opening(s), such as by electroplating (orCVD, sputtering, electroless plating, etc.). After the insulating layersare removed, the masses can function as free-standing resilient contactstructures which extend not only vertically above the surface of thecomponent, but also laterally from the location whereat they aremounted. In this manner, the contact structures are readily engineeredto be compliant in both the Z-axis as well as in the x-y plane (parallelto the surface of the component). This is described in greater detailhereinbelow with respect to FIGS. 2A-2C.

FIG. 2A illustrates an exemplary technique 200 for fabricating one of aplurality of free-standing resilient (spring) contact elements on asubstrate 202 which may be an active electronic component, includingsemiconductor devices such as memory chips, including semiconductordevices resident on a semiconductor wafer (not shown).

The substrate 202 has a plurality (one of may shown) or areas 212 on itssurface whereat the spring contact elements will be fabricated. In thecase of the substrate 202 being an electronic component (such as asemiconductor device), these areas 212 would be terminals (such as bondpads) of the electronic component.

Generally, the technique 200 involves applying a number (three shown) ofpatterned masking layers 204, 206 and 208 having openings onto thesurface of the substrate. The layers are patterned to have openings (asshown) aligned with the areas 212, and the openings are sized and shapedso that an opening in a one layer (e.g., 208, 206) extends further fromthe area 212 than an opening in an underlying layer (e.g., 206, 204,respectively). In other words, the first layer 204 has an opening whichis directly over the area 212. A portion of the opening in the secondlayer 206 is aligned over at least a portion of the opening in the firstlayer 204 and, conversely, a portion of the first layer 204 extendsunder a portion of the opening in the second layer 206. Similarly, aportion of the opening in the third layer 208 is aligned over at least aportion of the opening in the second layer 206 and, conversely, aportion of the second layer 206 extends under a portion of the openingin the third layer 208. The bottom portion of a given overall opening isdirectly over the selected area 212 and its top portion is elevated andlaterally offset from its bottom portion. As will be discussed ingreater detail hereinbelow, a conductive metallic material is depositedinto the openings, and the masking layers are removed, resulting in afreestanding contact structure having been fabricated directly upon thesubstrate with its base end secured to the substrate 202 at the area 212and its free end extending both above the surface of the substrate andlaterally-displaced from the area 212.

If required, such as for electroplating, a very thin (e.g., 450 μm)"seed" layer of conductive material 214 such as titanium/tungsten (TiW)may be deposited into the openings. Then, a mass of conductive metallicmaterial (e.g., nickel) 220 can be deposited by electroplating into theopenings.

FIGS. 2B and 2C illustrate a resulting spring contact element 220 havingits base (proximal) end 222 adjacent the area 212, and its free-end(tip) 224 elevated in the z-axis above the surface of the substrate 202as well as laterally offset in the x-axis and y-axis from the base end222.

As best viewed in FIG. 2C, the spring contact element 220 will reactpressure applied in the z-axis at its tip (distal) end 224, as indicatedby the arrow 232, such as would result from making a temporary pressureelectrical connection with a terminal (not shown) of another electroniccomponent (not shown). Compliance in the z-axis ensures that contactforce (pressure) will be maintained, and also accommodatesnon-planarities (if any) between terminals (not shown) on the otherelectronic component (not shown). Such temporary electrical connectionsare useful for making temporary connections to the electronic component202, such as for performing burn-in and/or testing of the component 202.

The tip (distal) end 224 is also free to move compliantly in the x- andy-directions, as indicated by the arrows 234 and 236, respectively. Thiswould be important in the context of joining (by soldering, or brazing,or with a conductive adhesive) the tip end 224 to a terminal (not shown)of another electronic component (not shown) which has a differentcoefficient of thermal expansion than the substrate (component) 202.Such permanent electrical connections are useful for assemblies ofelectronic components, such as a plurality of memory chips (each ofwhich is represented by the substrate 202) to another electroniccomponent such as an interconnection substrate such as a printed circuitboard ("PCB"; not shown).

By suitable choice of material and geometry, these plated-up structures220 can function as free-standing resilient contact structures whichhave been fabricated with very precise dimensions and very precisespacings from one another. For example, tens of thousands of such springcontact elements (220) are readily precisely fabricated on acorresponding number of terminals on semiconductor devices which areresident on a semiconductor wafer (not shown).

In this manner, there has been shown a method of fabricating springcontact elements (220) directly on a substrate (202) such as anelectronic component, such as a semiconductor device which may beresident on a semiconductor wafer, by applying at least one layer ofmasking material (104, 206, 208) on a surface of the substrate (202) andpatterning the masking layer to have openings extending from areas (212)on the substrate to positions which are spaced above the surface of thesubstrate and which also are laterally and/or transversely offset fromthe areas 212); by optionally seeding (214) the openings; by depositingat least one layer of a conductive metallic material into the openings;and by removing the masking material so that the remaining conductivemetallic material forms free-standing contact elements extending fromthe surface of the substrate, each contact element having a base endwhich is secured to a one of the areas of the substrate and having a tipend for making an electrical connection to a terminal of an electroniccomponent. The plated-up structures 220 are principally, preferablyentirely, metallic, and may be formed (fabricated) as multilayerstructures. The spring contact element 220 shown in FIG. 2C is aplated-up structure which is elongate and has a base (proximal) endwhich is mounted to the electronic component device 202 and free(distal) end (tip) at its opposite end for making a pressure contactwith a terminal (not shown) of another electronic component (not shown).

Suitable materials for the one or more layers of the contact structuresinclude, but are not limited to:

nickel, and its alloys;

copper, cobalt, iron, and their alloys;

gold (especially hard gold) and silver, both of which exhibit excellentcurrent-carrying capabilities and good contact resistivitycharacteristics;

elements of the platinum group;

noble metals;

semi-noble metals and their alloys, particularly elements of thepalladium group and their alloys; and

tungsten, molybdenum and other refractory metals and their alloys.

In cases where a solder-like finish is desired, tin, lead, bismuth,indium and their alloys can also be used.

The plated-up structures (120) are particularly well suited to makinginterconnections between microelectronic components and may have aheight (z-axis) on the order of 4-40 mils, such as 5-12 mils and anoverall length of 10-1000 mils such as 60-100 mils between theirattached base ends and their free ends (tips).

Spring Contact Elements Effecting Space-Translation

FIG. 3, corresponding to FIG. 15A of the aforementioned PCT PatentApplication No. US95/14909, discloses a technique 300 whereby individualones 302, 304 of a plurality of spring contact elements (compositeinterconnection elements) disposed on an electronic component 310 can besized and shaped so that their free ends (tips) 302a and 304a,respectively, are at a different pitch and orientation than their baseends 302b and 304b, respectively. In this manner, the spring contactelements themselves effect a type of space-translation which is pitchspreading. Evidently, performing space-translation in this mannerrequires that some of the spring contact elements be different (ratherthan identical) to others of the spring contact elements.

Routing Connections For The Spring Contact Elements

FIG. 4 discloses a technique 400 for forming conductive lines on asurface of an electronic component 402 Compare FIG. 3D of theaforementioned PCT Patent Application No. US95/14885.

A masking layer 404 is applied onto the surface of the electroniccomponent 402 and is patterned to have a plurality (two of many shown)of elongate openings 406 and 408, each elongate opening 406 and 408having a one end 406a and 408a, respectively, directly over (proximal) aterminal (not shown) of the electronic component 402, each elongateopening 406 and 408 having an other end 406b and 408b, respectively)remote (distal) from the terminal of the electronic component 402.

In a manner comparable to the fabrication of the spring contact elements220 described hereinabove, metallic material is deposited into theopenings 406 and 408, and the masking layer 404 is stripped off of theelectronic component 402, leaving behind a plurality of conductive linesextending from terminals of the electronic component to positions on theelectronic component which are remote from the terminals.

In the aforementioned, commonly-owned PCT Patent Application No.US95/14885, this technique was described in the context of providing(routing) conductive traces between (interconnecting) two or moreexisting terminals on an existing electronic component (e.g.,semiconductor device) 402, or for providing ground and/or power planesdirectly upon the electronic component 402, or for closely adjacent(e.g., interleaved) conductive lines which can serve as on-chipcapacitors, or for uniformizing deposition of the metallic material ontoother structures on the electronic component 402.

In the context of the present invention, the technique 400 is useful forrelocating the base ends of spring contact elements so as to be remotefrom the existing terminals to which they are electrically connected. Inother words, for forming "remote terminals" which are located elsewhereon the electronic component than the existing terminals.

Relocating The Spring Contact Elements ("Routing")

In applications where it is desired to fabricate a plurality of springcontact elements on an electronic component, whether the spring contactelements are of the composite interconnection (overcoated core element)type discussed with respect to FIGS. 1A-1C, or are of the plated-up typediscussed with respect to FIGS. 2A-2C, there are benefits to be derivedfrom having all of the spring contact elements be substantially the sameas one another--namely, substantially of the same shape, size, height,etc. This provides for better process control, and more uniformmechanical and electrical behavior of the spring contact elements.

According to the present invention, a plurality of substantiallyidentical spring contact elements can be fabricated upon an electroniccomponent (e.g., a semiconductor device) having a particular layout ofterminals (e.g., bond pads) in a manner that the free ends of the springcontact elements have a different layout than the bond pads. This is aform of space translation.

FIG. 5A illustrates a technique 500 for effecting space-translation withspring contact elements which are composite interconnection elements(compare 130).

An electronic component 502 such as a semiconductor device which may bea memory chip has a plurality (two of many shown) of terminals 504 on asurface thereof, according to conventional semiconductor fabricationtechniques. The component 502 is complete, and may have a toppassivation layer (not shown) with openings through which the terminals(bond pads) 502 can be accessed and connected to.

Prior to mounting, shaping and overcoating a wire stem in the mannerdescribed hereinabove with respect to FIGS. 1A-C, a plurality (two ofmany shown) of metal (conductive) lines 506 are formed on the surface ofthe component 502, each metal line extending from the terminal 504 alongthe surface of the device 502, to another location remote from theterminal 504. This metal line defines an "extended tail" for theresulting spring contact element 510 which is a compositeinterconnection element. At the remote position to which the extendedtail 506 extends, in other words at the end of the extended tail whichis distal from the terminal, the composite interconnection elementswhich are composite interconnection elements 510 are fabricated. Eachspring contact element 510 has a base end 512, a free end (tip) 514, anda body portion between the base and free ends.

In the illustration of FIG. 5A, it can be seen that the two springcontact elements 510 which are composite interconnection elements areidentical to one another, but that a one of the illustrated springcontact elements 510 has a longer extended tail 506 than the other ofthe illustrated spring contact elements 510.

FIG. 5B illustrates a technique 550 for effecting space-translation withspring contact elements which are plated-up structures (compare 220).

An electronic component 552 (compare 502) such as a semiconductor devicewhich may be a memory chip has a plurality (two of many shown) ofterminals 554 (compare 504) on a surface thereof, according toconventional semiconductor fabrication techniques.

In conjunction with the patterning of multiple masking layers (see 204,206, 208), seeding and depositing of metallic material described withrespect to FIGS. 2A-2C, the opening whereat the base end of theresulting plated-up structure will be formed is elongated to extend fromthe terminal 554 (compare 212) of the device 552 (compare 202), alongthe surface of the device 552, to another location remote from theterminal. This elongate opening, when filled with metallic material,will define an extended tail 556 for the resulting plated-up structure560. At the remote position to which the extended tail 556 extends, themasking layers are patterned to define the base end 562 of the resultingspring contact element 560. From this position (the base end), themasking layers are patterned to define the body portion and free end(tip) 564 of the resulting spring contact element 560.

In the illustration of FIG. 5B, it can be seen that the two springcontact elements which are plated-up structures 560 are identical to oneanother, but that a one of the illustrated spring contact elements 560has a longer extended tail 556 than the other of the illustrated springcontact elements 560.

According to these techniques (500, 550), a plurality of spring contactelements (510, 560) which are substantially identical with one anothercan be formed at locations on an electronic component (502, 552) whichare spatially-translated (positionally-removed) from the terminals (504,554) of the electronic component (502, 552). It is within the scope ofthis invention that spring contact elements which are not substantiallyidentical to one another can be disposed on conductive lines (510, 560),but such is generally not preferred.

As can be seen in FIGS. 5A and 5B, the terminals (504, 554) are disposedin a first pattern on the electronic component (502, 552) and that thedistal ends (514, 564) of the spring contact elements (510, 560) aredisposed in a second pattern which is different than the first pattern.The proximal ends (512, 562) of the spring contact elements (510, 560)are joined to ends of the conductive lines (506, 556) which are distalfrom the terminals (504, 554). Typically, the proximal ends (512, 562)of the spring contact elements (510, 560) are disposed in a patternwhich is comparable to the second pattern of the distal ends (514, 564).In cases where the spring contact elements (510, 560) are absolutelyidentical to one another, the pattern of the proximal ends (512, 562)will be identical to the pattern of the distal ends (514, 564).

It is within the scope of this invention that the extended tails (506,556) can comprise metallic depositions in two or more masking layers(see, e.g., FIG. 14A hereinbelow), and that they can cross over oneanother without shorting out (see, e.g., FIG. 14B hereinbelow) to effectcomplex routing schemes, utilizing conventional semiconductormetallization techniques.

An exemplary application of fabricating a plurality of identical springcontact elements on an electronic component (e.g., a semiconductordevice) having a particular layout of terminals (e.g., bond pads) in amanner that the free ends (tips) of the spring contact elements have adifferent positional layout than the terminals of the component is shownin FIG. 4A of commonly-owned, copending U.S. patent application Ser. No.08/863,511 filed May 27, 1997, which discloses offset stacking aplurality (two or more) of bare unpackaged semiconductor devices such asmemory chips, each chip having a plurality of spring contact elementsextending from an edge thereof, so that all of the spring contactelements of the stacked chips can individually make contact withcorresponding terminals of an interconnection substrate.

An Application For Elongate Tails

FIGS. 6A and 6B illustrate an exemplary application 600 for the springcontact elements having elongate tails of the present invention. CompareFIG. 5 of the aforementioned, PCT Patent Application No. US97/08271.

A plurality of spring contact elements 602 of the type describedhereinabove with respect to FIG. 2 and 5B are arranged on the surface ofa first electronic component 604 in a "fan-in pattern". Each springcontact element 602 has a "tail extension" 606 (compare 556) having aone (proximal) end joined to a terminal 608 of the first electroniccomponent 604. The terminals 608 of the first electronic component 604are disposed about a periphery of the first electronic component 604 ata first, relatively coarse pitch (spacing). The tail extensions(conductive lines) 606 extend generally radially inward from theterminals 604 towards the center of the first electronic component 604.The base ends 602b (compare 222) of the spring contact elements 602 arejoined to the distal ends of the tail extensions 606. The main bodyportions 602c of the spring contact elements 602 extend generallyradially inward from the tail extensions 606, partway to the center ofthe first electronic component 604. Thus, the tip ends 602a (compare224) of the spring contact elements 602 are disposed in a peripheralpattern at a much closer spacing (finer pitch) than the terminals 608 ofthe first electronic component 604. In this manner, the tip ends 602a ofthe spring contact elements 602 can make contact with terminals 610 of asecond electronic component 612 which are disposed at a much finer pitchthan the terminals 608 of the first electronic component 604. Asmentioned hereinabove, the tip ends 602a of the spring contact elements602 may make either temporary (pressure) or permanent (soldered)connections with the terminals 610 of the second electronic component612. This is best viewed in FIG. 6B.

Another Application For Elongate Tails

FIGS. 7A and 7B illustrate another exemplary application 700 for thespring contact elements having elongate tails of the present invention.Compare FIG. 6 of the aforementioned, PCT Patent Application No.US97/08271.

A plurality of spring contact elements of the type described hereinabovewith respect to FIG. 2 and 5B are arranged on the surface of a firstelectronic component 702 in the following manner.

The first electronic component 702 has four side edges 702a, 702b, 702cand 702d, has a centerline 704, and has a plurality of terminals 706disposed in opposing side areas 708 and 710 on its top surface.

In the side area 708, which is adjacent the side edge 702a, theterminals 706 are "staggered" so that a first portion 706a of theterminals 706 are disposed relatively close to the side edge 702a of thefirst electronic component 702, and a second portion 706b of theterminals 706 are disposed somewhat closer to the centerline 704 of(i.e., farther from the side edge 702a of) the first electroniccomponent 702. As illustrated, the terminals 706a and 706b alternatebetween relatively close to the side edge 702a and farther from the sideedge 702a.

In the side area 710, which is adjacent the side edge 702c, theterminals 706 are "staggered" so that a first portion 706c of theterminals 706 are disposed relatively close to the side edge 702c of thefirst electronic component 702, and a second portion 706d of theterminals 706 are disposed somewhat closer to the centerline 704 of(farther from the side edge 702c of) the first electronic component 702.As illustrated, the terminals 706c and 706d alternate between relativelyclose to the side edge 702c and farther from the side edge 702c.

A plurality of spring contact elements 720 (compare 220) are formed onthe surface of the first electronic component 702 in the followingmanner. A first plurality of tail extensions 722 have their one(proximal) ends joined to the terminals 706a, and extend towards thecenterline 704 of the first electronic component 702. A second pluralityof tail extensions 724 have their one (proximal) ends joined to theterminals 706b, and extend towards the centerline 704 of the firstelectronic component 702. A third plurality of tail extensions 726 havetheir one (proximal) ends joined to the terminals 706c, and extendtowards the centerline 704 of the first electronic component 702. Afourth plurality of tail extensions 728 have their one (proximal) endsjoined to the terminals 706d, and extend towards the centerline 704 ofthe first electronic component 702. The tail extensions 722, 724, 726and 728 are all parallel to one another, but they need not be.

A first portion 720a of the spring contact elements 720 are joined bytheir base ends to the distal ends of the first plurality of tailextensions 722, and their tip ends are disposed at the centerline 704 ofthe first electronic component 702.

A second portion 720b of the spring contact elements 720 are joined bytheir base ends to the distal ends of the second plurality of tailextensions 724, and their tip ends are disposed at the centerline 704 ofthe first electronic component 702.

A third portion 720c of the spring contact elements 720 are joined bytheir base ends to the distal ends of the third plurality of tailextensions 726, and their tip ends are disposed at the centerline 704 ofthe first electronic component 702.

A fourth portion 720d of the spring contact elements 720 are joined bytheir base ends to the distal ends of the fourth plurality of tailextensions 728, and their tip ends are disposed at the centerline 704 ofthe first electronic component 702.

In this manner, the spring contact elements 720 (720a, 720b, 720c, 720d)can be fabricated so as to be substantially identical to one another,yet have their tip (contact ends) arranged (laid out) entirelydifferently than the terminals 706a, 706b, 706c and 706d, respectively,to which they are electrically connected via the conductive lines(elongate tails) 722, 724, 726 and 728, respectively.

In use, the first electronic component 702 makes electrical connectionsto a second electronic component 732, the tip (contact) ends of thespring contact elements contacting corresponding terminals 734 on thesecond electronic component 732. This is best viewed in FIG. 7B.

The showing of only a limited variety of different-length conductivelines is merely exemplary and it should be understood that it is withinthe scope of this invention that a plurality of conductive lines havinga greater number of variations (e.g., differences in length, as well asin their path along the surface of the electronic component) can bedisposed on an electronic component to effect numerous space-translationschemes.

Relocating The Bases Of Two Or More Springs Which Are Connected To ASingle Terminal Of The Electronic Component

In certain instances, it may be desireable not only to relocate the baseof a single spring contact element, but to have two or more "relocated"spring contact elements connected to a single terminal of the electroniccomponent.

FIG. 8A illustrates an embodiment 800 of the invention. An electroniccomponent 802 has a terminal 804. An elongate conductive line (tail) 806is formed on the electronic component 802 with its proximal end joinedto the terminal 804. A one spring contact element 810 is joined by itsbase to the distal end of the elongate conductive line 806. Anotherspring contact element 812 is joined by its base to the conductive line806 at a position on the conductive line 806 which is remote from theproximal end of the conductive line 806, yet which is not at the distalend of the conductive line 806. The two spring contact elements 810 and812 are of the composite interconnection type (compare 130), and arepreferably identical to one another.

FIG. 8B illustrates another embodiment 850 of the invention. Anelectronic component 852 (compare 802) has a terminal 854 (compare 804).An elongate conductive line 856 (compare 806) is formed on theelectronic component 852 with its proximal end joined to the terminal854. A one spring contact element 860 (compare 810) is joined by itsbase 860a (compare 222) to the distal end of the elongate conductiveline 856. Another spring contact element 862 (compare 812) is joined byits base 862a (compare 222) to the conductive line 856 at a position onthe conductive line 856 which is remote from the proximal end of theconductive line 856, yet which is not at the distal end of theconductive line 856. The two spring contact elements 860 and 862 are ofthe plated-up structure type, and are preferably identical to oneanother.

Relocating Terminals Of An Electronic Component

The elongate tails (conductive lines) described hereinabove permitspring contact elements to be located other than at the positions ofexisting terminals of an existing electronic component. For example, asemiconductor device may have a plurality of bond pad terminals locatedabout its periphery, outside of a central area which contains activecircuitry. The present invention makes it possible to mount springcontact elements directly above (atop) the active components of thesemiconductor device.

An example is shown schematically in FIG. 9, wherein an electroniccomponent 902 has an existing terminal 904 at a first position. It isdesired to fabricate or to mount a spring contact element (not shown) ata position on the electronic component 904 which is remote from theterminal 904, for example directly over active circuitry on theelectronic component 902. To this end, a "relocated terminal" 906 isfabricated at a position which is remote from the terminal 904 and iselectrically connected, as shown by the dashed line 908 to the terminal904. A spring contact element (not shown) of any of the types describedhereinabove can then have its base end secured to the relocated terminal906.

Generally, the "relocated terminal" 906 is simply the distal end of aconductive line of the type described hereinabove, including anyposition on the conductive line which is remote from the proximal end ofthe conductive line. FIG. 9 illustrates that the distal end of theconductive line can be formed to have a large surface area. Varioustechniques of effecting the electrical connection between the terminal904 and the relocated terminal 906 are now described.

Filling Openings In A Masking Layer With Conductive Material

FIGS. 9A and 9B illustrates a technique 910 for fabricating a relocatedterminal and for effecting an electrical connection between therelocated terminal and an existing terminal of an electronic component912 (compare 902). A masking layer 920 is applied over the surface ofthe electronic component 912 and is patterned to have a first portion924 of an opening directly over the existing terminal 914 (compare 904)of the electronic component 912, a second portion 926 of the opening ata position remote from the existing terminal (compare 906), and anelongate opening 928 (compare 908) extending between the first andsecond openings 924 and 926, respectively. The openings 924, 926 and 928are contiguous with one another, and are filled with conductive material930. A portion of the conductive material 930 fills the opening 924which is directly atop the existing terminal, and is joined thereto.This will become the proximal end of the conductive line (elongatetail). The conductive material 930 also fills the opening 926 andbecomes the relocated terminal (compare 906). The conductive material930 also fills the opening 928 and becomes an elongate conductive line(compare 908) joining (electrically connecting) the conductive materialin the opening 924 to the conductive material in the opening 926. Thetechnique 910 illustrated in FIG. 9A is comparable to the technique 400described with respect to FIG. 4. In both, openings in a masking layerare created and filled with conductive (metallic) material.

As shown in FIG. 9B, the conductive material 930 deposited in theopenings 924, 926 and 928 can be very thin, and may simply be a "seedlayer" to support subsequent plating. A core element 934 (compare 102)can be joined to the seed layer 930 at a position within the opening926. Then, both the core element 934 and the seed layer 930 can beovercoated with a conductive material 936 (compare 134).

An Alternate Technioue ("Spot Gold")

FIG. 10 illustrates a first (preliminary) step 1000 in another of twosimilar techniques for fabricating a relocated terminal and foreffecting an electrical connection between the relocated terminal and anexisting terminal of an electronic component. A first of thesetechniques is described with respect to FIGS. 10A-10C. A second of thesetechniques is described with respect to FIGS. 10D-10G. In bothtechniques, gold is applied and patterned ("spot gold").

In the technique illustrated in FIGS. 10A-10C (including the preliminarystep shown in FIG. 10), a layer 1012 of titanium-tungsten (TiW) isapplied onto the surface of an electronic component 1002. This layer1012 is suitably a blanket layer, covering the entire surface of theelectronic component 1002, and suitable has a thickness of approximately4500 Å (Angstroms).

Then, a masking layer 1020 (compare 920) such as photoresist is appliedover the layer 1012 and is patterned to have an opening with portions1004 (compare 904, 924), 1006 (compare 906, 926) and 1008 (compare 908,928). The portion 1004 of the opening is directly over an existingterminal 1014 (compare 914) of the electronic component 1002. Theportion 1006 is remote from the location of the terminal 1014. Theportion 1008 extends between the portions 1004 and 1006.

Next, as best viewed in FIG. 10A, a layer 1016 of gold is applied withinthe opening. This layer 1016 is applied in any suitable manner andsuitably has a thickness of approximately 1200 Å. The patterned layer1016, and the portion of the layer 1012 which lies immediatelyunderneath the patterned layer 1016 comprise the conductive line which"relocates" the terminal for remote attachment of the spring contactelement.

Next, as best viewed in FIG. 10B, a core element 1034 (compare 934) isattached to the layer 1016 at a position remote from the terminal 1014,such as within the portion 1006 of opening in the masking layer 1020.Then, the core element 1034 and the patterned layer 1016 is overcoatedwith a layer 1036 (compare 936) of a metallic material in the mannerdescribed hereinabove with respect to the composite interconnectionelement 130.

As is evident, the first metallic layer 1012 will electrically connectall of a plurality of openings in the masking layer to one another,consequently all of the spot gold patterns (1016) to one another,consequently all of the core elements 1034 to one another. In thisrespect, the layer 1012 serves as a "shorting layer" to facilitate theapplication both of the spot gold 1016 and of the overcoat material 1036by electroplating techniques. The final overcoat material 1036 issuitably nickel or an alloy thereof.

As best viewed in FIG. 10C, in a final step of this first technique, themasking layer 1020 is removed, and the portions of the shorting layer1012 which were covered by the masking layer 1020 exposed. By selectivechemical etching, these portions of the shorting layer 1012 which werenot spot-gold coated may readily be removed, thereby electricallyisolating a one spring contact element from other spring contactelements (not shown) in the plurality of spring contact elements whichhave been mounted to the electronic component 1002.

In the technique illustrated in FIGS. 10C-10G (including the preliminarystep shown in FIG. 10), a layer 1012 of titanium-tungsten (TiW) isapplied onto the surface of an electronic component 1002. This layer1012 is suitably a blanket layer, covering the entire surface of theelectronic component 1002, and suitable has a thickness of approximately4500 Å (Angstroms).

Then, a masking layer 1020 (compare 920) such as photoresist is appliedover the layer 1012 and is patterned to have an opening with portions1004 (compare 904, 924), 1006 (compare 906, 926) and 1008 (compare 908,928). The portion 1004 of the opening is directly over an existingterminal 1014 (compare 914) of the electronic component 1002. Theportion 1006 is remote from the location of the terminal 1014. Theportion 1008 extends between the portions 1004 and 1006.

Next, a layer 1016 of gold is applied within the opening. This layer1016 is applied in any suitable manner and suitably has a thickness ofapproximately 1200 Å. The patterned layer 1016, and the portion of thelayer 1012 which lies immediately underneath the patterned layer 1016comprise the conductive line which "relocates" the terminal for remoteattachment of the spring contact element.

Up to this point, the second technique is quite similar to the firsttechnique described with respect to FIGS. 10A-10C Next, as best viewedin FIG. 10D, the masking layer 1020 is removed, resulting in a pluralityof spot gold patterns (lines) atop the first conductive layer 1012.

Next, as best viewed in FIG. 10E, a second masking layer 1040 (compare1020) is applied and patterned so as to cover all but a portion of thespot gold layer 1016 which is remote from the terminal 1014 at aposition corresponding to the portion 1006 of the opening in the earliermasking layer 1020 which has been removed. In other words, the maskinglayer 1040 has an opening 1042 at the same "remote terminal" position asthe portion 1006 of previous masking layer 1020.

Next, as best viewed in FIG. 10F, a core element 1054 (compare 1034) isattached to the layer 1016 within the opening 1042. Then, the coreelement 1054 and the portion of the patterned layer 1016 which isexposed within the opening 1042 is overcoated with a layer 1056 (compare1036) of a metallic material in the manner described hereinabove withrespect to the composite interconnection element 130.

As with the previously-described technique, the first metallic layer1012 will electrically connect all of a plurality of openings (1042) inthe masking layer (1040) to one another, consequently all of the spotgold patterns (1016) to one another, consequently all of the coreelements 1054 to one another, the first metallic layer 1012 serving as a"shorting layer" to facilitate electroplating.

As best viewed in FIG. 10G, in a final step of this second technique,the masking layer 1040 is removed, leaving portions of the shortinglayer 1012 which were not spot-gold coated completely exposed. Byselective chemical etching, these portions of the shorting layer 1012may readily be removed, thereby electrically isolating a one springcontact element from other spring contact elements (not shown) in theplurality of spring contact elements which have been mounted to theelectronic component 1002.

Mounting Pre-Fabricated Spring Contact Elements To Conductors

There have been discussed, hereinabove, a number of techniques forfabricating spring contact elements (such as composite interconnectionelements) at remote positions on conductors which may be conductivelines (extended tails) extending from terminals of an electroniccomponent, as well for fabricating extended tails extending from basesof spring contact element in one fell swoop. There are now describedtechniques for prefabricating spring contact elements, and joining theprefabricated spring contact elements to remote positions (e.g., distalends) of conductive lines extending from existing terminals of anelectronic component.

FIGS. 11A-11B are comparable to FIGS. 5C and 5F of commonly-owned,copending U.S. patent application Ser. No. 08/788,740 filed Jan 24, 1997(status: pending) and its counterpart PCT Patent Application No.US96/08107 filed May 24, 1996 (Published Nov. 28, 1996 as WO96/37332)and illustrate how a plurality of composite interconnection elements canbe prefabricated on a sacrificial substrate, then "gang-transferred" toterminals of an electronic component. For purposes of the presentinvention, the prefabricated spring contact elements aregang-transferred to remote positions on conductive lines (extendedtails).

FIG. 11A shows a technique 1100 whereby a plurality (two of many shown)of composite interconnection elements 1102 which have been fabricated,including overcoated, on contact tip structures 1104 which have beenformed in a sacrificial substrate 1106 such as aluminum or silicon.

FIG. 11B shows the sacrificial substrate 1106, with compositeinterconnection elements 1102 (compare 510 hereinabove) extendingtherefrom, positioned above an electronic component 1110 (compare 502hereinabove) so that the free ends of the composite interconnectionelements 1102 are adjacent conductive lines 1112 (viewed endwise,compare 506 hereinabove) which are resident on the electronic component1110. The free ends of the composite interconnection elements 1102 arethen joined (such as by soldering or brazing, or with a conductiveadhesive) with a joining material 1114 to the conductive lines 1112.

Next, as shown in FIG. 1C, the sacrificial substrate 1106 is removed,such as with heat or by chemical etching. In this manner, the gang (enmasse) transfer of a plurality of composite interconnection elements1102 is effected to a corresponding plurality of conductive lines 1114on an electronic component. It is within the scope of this inventionthat the spring contact elements 1102 are or are not provided with theillustrated prefabricated contact tip structures 1104.

FIGS. 11A-11C, described hereinabove, are illustrative of joining aplurality of prefabricated spring contact elements of the compositeinterconnection type to a corresponding plurality of conductive linesextending from terminals on an electronic component. In a similarmanner, a plurality of prefabricated spring contact elements of theplated-up structure type can be joined to a plurality of conductivelines extending from terminals on an electronic component.

FIGS. 12A-12C are comparable to FIGS. 4A-4C of the aforementioned U.S.Ser. No. 08/802,054 and PCT US97/08271, and illustrate how a pluralityof plated-up type spring contact elements can be prefabricated on asacrificial substrate, then "gang-transferred" to terminals of anelectronic component. For purposes of the present invention, theprefabricated spring contact elements are gang-transferred to remotepositions on conductive lines (extended tails).

FIG. 12A shows a technique 1200 whereby a plurality (two of many shown)of plated-up spring contact elements 1202 (compare 1102) which have beenfabricated on a sacrificial substrate 1206 (compare 1106) such as asilicon wafer, by repeated masking, etching and deposition of metallicmaterials. The spring contact elements 1202 have pointy contact features1204 (compare 1104) at their contact ends which are suitably in the formof truncated pyramids.

FIG. 12B shows the sacrificial substrate 1206, with plated-up springcontact elements 1202 disposed on a surface thereof positioned above anelectronic component 1210 (compare 1110) so that the contact tipfeatures 1204 are adjacent conductive lines 1212 (compare 1112) whichare resident on the electronic component 1210. The tip ends of theplated-up spring contact elements 1202 are then joined (such as bysoldering or brazing, or with a conductive adhesive) with a joiningmaterial 1214 (compare 1114) to the conductive lines 1212.

Next, as shown in FIG. 12C, the sacrificial substrate 1206 is removed,such as with heat or by chemical etching. In this manner, the gang (enmasse) transfer of a plurality of spring contact elements 1202 iseffected to a corresponding plurality of conductive lines 1212 on anelectronic component. It should be understood that for permanentlyjoining the spring contact elements 1202 to the conductive lines 1212that the contact features 1204 are somewhat superfluous, their primarypurpose being to effect reliable pressure connections to terminals ofother electronic components. However, during joining the spring contactelements 1202 to the conductive lines 1212, these pointy features 1204may help keep the components in place during reflow soldering (e.g.).FIG. 12C illustrates the free ends of the spring contact elements 1202making contact with terminals 1220 of another electronic component 1222.

Joining Contact Tip Structures To The Spring Contact Elements

The subject of providing spring contact elements with contact tipstructures which have been fabricated to have a distinct metallurgy andshape has been described in a number of the aforementioned patentapplications.

FIGS. 13A and 13B are comparable to FIGS. 6D and 6E of theaforementioned U.S. Ser. No. 08/788,740 and PCT US96/08107 andillustrate how a plurality of contact tip structures can beprefabricated on a sacrificial substrate, then "gangtransferred" to endsof spring contact elements which are resident on an electroniccomponent. This is somewhat akin in nature to the previously-describedtechniques for gang transferring prefabricated spring contact elementsto remote positions on conductive lines (extended tails).

FIG. 13A shows a technique 1200 whereby a plurality (two of many shown)of prefabricated contact tip structures 1302 (compare 1202) have beenfabricated on a sacrificial substrate 1306 (compare 1206) such as asilicon wafer, by masking, etching and deposition of metallic materials.A release mechanism 1308 comprising one or more layers is disposedbetween the contact tip structures 1302 and the sacrificial substrate1306.

The sacrificial substrate 1306, with contact tip structures 1302disposed on a surface thereof is positioned above an electroniccomponent 1310 (compare 1210) so that the contact tip structures 1302are against free ends of spring contact elements 1332 extending fromremote regions of conductive lines 1312 (compare 1212) on the electroniccomponent 1310. The contact tip structures 1302 are then joined (such asby soldering or brazing, or with a conductive adhesive) with a joiningmaterial 1314 (compare 1214) to the spring contact elements 1332.

Next, as shown in FIG. 13B, the sacrificial substrate 1306 is removed,such as with heat or by chemical etching. In this manner, the gang (enmasse) transfer of a plurality of contact tip structures 1302 iseffected to a corresponding plurality of spring contact elements 1332which are disposed on conductive lines 1312 on an electronic component1310.

Multi-Level Conductive Lines

FIG. 14A illustrates a technique 1400 whereby a conductive line, such asthose described hereinabove, is disposed in two distinct layers atop theelectronic component 1402 (compare 502). The electronic component 1402has a terminal 1404 (compare 504). A first portion 1406a of theconductive line has a first end directly atop the terminal 1404, and hasa second opposite end. The first portion 1406a of the conductive line isin a first layer, surrounded by an insulating material 1420. A secondportion 1406b of the conductive line is in a second layer, atop thefirst layer, is surrounded by an insulating material 1422, has a firstend overlapping the second end of the first portion 1406a, and has asecond opposite end remote from the terminal 1404. A spring contactelement 1410 (compare 510) is mounted to a remote (from the terminal1404) portion of the second portion 506b of the conductive line. Theconcept illustrated here can be extended to fabricate conductive lineshaving portions in more than two layers.

Crossing Over

FIG. 14B illustrates a technique 1450 whereby at least one of aplurality of conductive lines, such as those described hereinabove, isdisposed in multiple distinct layers atop the electronic component 1452(compare 1402). The electronic component 1452 has a terminal 1454(compare 1404). A first portion 556a (compare 506a) of a firstconductive line has a first end directly atop the terminal 1454, and hasa second opposite end. The first portion 1456a of the first conductiveline is in a first layer, surrounded by an insulating material 1470(compare 1420). A second portion 556b (compare 506b) of the firstconductive line is in a second layer, atop the first layer, issurrounded by an insulating material 1472 (compare 1422), has a firstend overlapping the second end of the first portion 1456a, and has asecond opposite end remote from the terminal 1404. In this example, aconductive spacer block 1457 is disposed mounted to a remote (from theterminal 1404) portion of the second portion 1456b of the firstconductive line, and a spring contact element 1460 (compare 1410) ismounted to the conductive spacer block 1457. The spacer block 1457 is ina third layer wherein, as will be seen, there is a second conductiveline having a portion 1458 crossing over a portion 1456a of the firstconductive line.

A second conductive line originates from another terminal (not shown) onthe electronic component 1452. In a manner similar to that of the firstconductive line having portions in various ones of multiple layers, thesecond conductive line also has portions (one, 1458, shown) in variousones of multiple layers. As illustrated, a portion 1458 of the secondconductive line crosses over the portion 1456a of the first conductiveline, and a spring contact element 1462 (compare 1460) is mounted to theportion 1462 of the second conductive line at a position which is remotefrom the terminal. In this manner, complex routing schemes can beeffected. A final passivation (protective) layer 1480 of encapsulatingmaterial may be applied over the conductive lines.

Although the invention has been illustrated and described in detail inthe drawings and foregoing description, the same is to be considered asillustrative and not restrictive in character--it being understood thatonly preferred embodiments have been shown and described, and that allchanges and modifications that come within the spirit of the inventionare desired to be protected. Undoubtedly, many other "variations" on the"themes" set forth hereinabove will occur to one having ordinary skillin the art to which the present invention most nearly pertains, and suchvariations are intended to be within the scope of the invention, asdisclosed herein.

For example, the concept of fabricating plated-up structures having longtails effecting routing can be extended in virtually an unlimitedmanner. For example, spring contact elements can be fabricated on asemiconductor device having a plurality of bond pads arranged along itsperiphery (in a peripheral pattern) so that the tips (free ends) of thespring contact elements are disposed in an area array arrangement, orvice-versa.

For example, the spring contact elements may be heat-treated to enhancetheir mechanical characteristics.

What is claimed is:
 1. An electronic component, comprising:a terminal onthe electronic component; a first remote area on the component which isremote from the terminal; an electrical connection between the terminaland the first remote area; and a first spring contact element disposedat the first remote area, the spring contact element furthercomprising:a precursor element, of a first material, attached to andextending from the first remote area; and a second material deposited ina form determined significantly by the precursor element, wherein theprecursor element without the second material is flexible, and thesecond material is resilient.
 2. The electronic component, according toclaim 1, wherein:the electrical connection comprises a conductive tracehaving a proximal end joined to the terminal; and the first remote areacomprises a position on the conductive trace which is remote from theproximal end of the conductive line.
 3. The electronic component,according to claim 1, further comprising:a plurality of terminals on theelectronic component; a plurality of first remote areas on theelectronic component; a plurality of electrical connections, each of theplurality of electrical connections extending between selected ones ofthe terminals and selected ones of the first remote areas; and aplurality of spring contact elements, each of the plurality of springcontact elements disposed at a one of the remote areas.
 4. Theelectronic component, according to claim 3, further comprising:a firstlayer on the electronic component having a first pattern of firstconductive traces; a second layer on the electronic component having asecond pattern of second conductive traces; selected portions of thefirst conductive traces joined to selected ones of the terminals; andselected portions of the second conductive traces electrically connectedto selected ones of the first conductive traces; wherein the firstremote areas are on the second conductive traces.
 5. The electroniccomponent, according to claim 4, further comprising:a third layer on theelectronic component having a third pattern of third conductive traces;wherein the selected portions of the second conductive traceselectrically are connected to the selected ones of the first conductivetraces via selected portions of the third conductive layer.
 6. Theelectronic component, according to claim 3, wherein:the electricalconnections comprise a plurality of conductive lines; and at least oneof the plurality of conductive lines crosses over another one of theplurality of conductive lines without electrically contacting the otherone of the conductive lines.
 7. The electronic component, according toclaim 3, wherein:the spring contact elements are substantially identicalto one another.
 8. The electronic component, according to claim 3,wherein:the plurality of terminals are disposed in a first pattern onthe component; each of the plurality of spring contact elements has acontact region, the contact region displaced away from the electroniccomponent and moveable toward the electronic component; the contactregions of the spring contact elements are arranged in a second pattern;and the second pattern is different from the first pattern.
 9. Theelectronic component, according to claim 8, wherein:the first patterncomprises a peripheral pattern having a first pitch; the second patterncomprises a peripheral pattern having a second pitch; and the secondpitch is different than the first pitch.
 10. The electronic component,according to claim 8, wherein:the second pattern comprises a row. 11.The electronic component, according to claim 8, wherein:the firstpattern comprises a row.
 12. The electronic component, according toclaim 3, wherein:each of the plurality of spring contact elements has acontact region, the contact region displaced away from the electroniccomponent and moveable toward the electronic component; the plurality ofterminals are disposed in a peripheral pattern on the component; and theplurality of contact regions of the spring contact elements are arrangedin an area array.
 13. The electronic component, according to claim 1,further comprising:a second remote area on the electronic component, thesecond remote area electrically connected to the terminal; and a secondspring contact element disposed at the second remote area.
 14. Theelectronic component, according to claim 1, wherein:the first springcontact element is a composite interconnection element.
 15. Theelectronic component, according to claim 1, wherein:the first springcontact element is a plated-up structure.
 16. The electronic component,according to claim 1, wherein:the electronic component is selected fromthe group consisting of a semiconductor device, a memory chip, a portionof a semiconductor wafer, a space transformer, a probe card, a chipcarrier, and a socket.
 17. A semiconductor device with an integralcontact element, comprising:a semiconductor device; a bond pad on thesemiconductor device; a conductive trace on the semiconductor deviceextending from the bond pad to a position which is remote from theterminal; a spring contact element having a base end at a region of theconductive trace which is remote from the bond pad, the spring contactelement having a contact region disposed above the surface of thesubstrate and offset from the base end, the spring contact elementfurther comprising:a precursor element, of a first material, attached toand extending from the first remote area; and a second materialdeposited in a form determined significantly by the precursor element,wherein the precursor element without the second material is flexible,and the second material forms a spring.
 18. The semiconductor device,according to claim 17, wherein:the spring contact element comprises acomposite interconnection element.
 19. The semiconductor device,according to claim 17, wherein:the spring contact element comprises aplated-up structure.
 20. The semiconductor device, according to claim17, wherein:the semiconductor device is a memory chip.
 21. Theelectronic component, according to claim 1, wherein the first materialincludes a material selected from the group consisting of gold, aluminumand copper.
 22. The electronic component, according to claim 1, whereinthe spring contact element is resilient and the second materialdominates the resiliency of the spring contact element.
 23. Theelectronic component, according to claim 1, wherein the second materialis stronger than the precursor element.
 24. The electronic component,according to claim 1, wherein the second material is a coating whichenvelops the precursor element.
 25. The electronic component, accordingto claim 1, wherein the second material comprises a material selectedfrom the group consisting of nickel, cobalt and iron.
 26. The electroniccomponent, according to claim 1, wherein the second material isdeposited directly on the precursor element.
 27. The semiconductordevice, according to claim 17, wherein the first material includes amaterial selected from the group consisting of gold, aluminum andcopper.
 28. The semiconductor device, according to claim 17, wherein thespring contact element is resilient and the second material dominatesthe resiliency of the spring contact element.
 29. The semiconductordevice, according to claim 17, wherein the second material is strongerthan the precursor element.
 30. The semiconductor device, according toclaim 17, wherein the second material is a coating which envelops theprecursor element.
 31. The semiconductor device, according to claim 17,wherein the second material comprises a material selected from the groupconsisting of nickel, cobalt and iron.
 32. The semiconductor device,according to claim 17, wherein the second material is deposited directlyon the precursor element.